Osteotomy guide

ABSTRACT

A new osteotomy guide for guiding saw blades when making an osteotomy cut in a bone is disclosed. Osteotomy is the surgical dividing of bone. The guide includes a base, a pair of prongs and a handle. The base includes a bore for passage of a K-wire or other guide pin. The prongs define a slot for passage of a surgical saw blade. The bore and slot are deeper than prior art osteotomy guides and thus stabilize the guide and the blade relative to the guide pin so that the plane of the saw blade remains parallel to the guide pin. This ensures that in multiple-cut osteotomy procedures all the planes of opposing cuts will exactly coincide when the cut ends are reattached.

The invention described herein may be manufactured and used by or forthe Government of the United States for all governmental purposeswithout the payment of any royalty.

BACKGROUND OF THE INVENTION

The present invention relates generally to osteotomy guides for guidingsaw blades when making an osteotomy cut in a bone, and more specificallyto an osteotomy guide that both guides and stabilizes the blade so thatplanes of opposing cuts will exactly coincide.

Osteotomy is the surgical dividing of bone. An osteotomy proceduregenerally involves cutting completely through a bone, often removing asection of bone, and then reattaching the cut ends in a new positionrelative to each other to correct many types of bone deformities andmisalignments and to alleviate other conditions. An example osteotomyprocedure is a bunionectomy. A bunion, an inflamed swelling usually onthe inside (medial side) of the first metatarsal phalangeal joint of thebig toe, can be excruciatingly painful, particularly when continuouslyrubbed against the inside of a patient's shoe. A patient will oftencompensate for the pain by changing the way he or she walks and even bygiving up the wearing of shoes. In a bunionectomy, a surgeon willcompletely divide the bone near the bunion, slide or displace the toeend of the bone toward the outside (lateral side) of the foot andreattach the two cut ends. This moves the affected metatarsal phalangealjoint away from the inside of the patient's footware, reduces pain andaggravation and may even prevent future inflammation. Another exampleosteotomy procedure would be to correct bowleggedhess by cutting out andremoving a wedge-shaped section of a knee and then repositioning the cutends together so that the leg is straightened.

An osteotomy typically involves more than one cut straight through abone. A single cut leaving two plane surfaces to be reattached ismechanically weak. To provide mechanical strength and stability to therefastened bone, several cuts are generally made so that one cut endwill nest into the opposite cut end, similar to, but generally not soelaborate as, a woodworking tongue-and-groove joint. An examplemultiple-cut osteotomy is a V-cut. The apex of the V is usually definedby a surgical guide pin, using a K-wire, that is drilled in place aftera surgeon decides where the cuts should be made.

In any osteotomy where more than two cuts are required, success requiresthat the planes of opposing cuts coincide with each other. This isparticularly difficult when the cuts are made at an angle. If they donot coincide, then the bone will be misaligned when reattached andcorrection will require substantial additional cutting. Imagine, forexample, the difficulty of correcting a woodworking tongue-and-groovejoint if the walls of the tongue or the groove were at different anglesrelative to each other. A particular difficulty facing surgeonsperforming osteotomy procedures is that they have only a two-dimensionalview for making three-dimensional cuts.

Prior art osteotomy guides which attach to a guide pin, such as theScott Universal, the Austin/Scarf and the Austin/Chevron, do not providestability for the osteotomy blade and do not provide a feature formodifying the angle of osteotomy cuts. The Scott RCE osteotomy guidedoes provide for modifying the angle of osteotomy cuts, but does notstabilize the osteotomy blade. The Scott RCE osteotomy guide is alsolarge and bulky, necessitating excessive dissection to make room for theguide.

The result of using these prior art osteotomy guides is that asuccessful surgical outcome is not only too highly dependent on asurgeon's skill, but also that they require excessive tissue excision sothat the surgeon can see where he or she is cutting.

Thus it is seen that there is a need for an improved osteotomy guidethat helps ensure in an osteotomy procedure accurate placement of asurgical saw blade so that the planes of opposing osteotomy cuts willexactly coincide.

It is, therefore, a principal object of the present invention to providean osteotomy guide that, in addition to guiding a surgical saw blade,also stabilizes and supports the saw blade.

It is another object of the present invention to provide an osteotomyguide that holds the saw blade parallel to the guide pin.

It is a feature of the present invention that it holds the saw bladeparallel to a guide pin during cutting.

It is another feature of the present invention that it ensures preciseplacement of the saw blade and accurate cuts.

It is a further feature of the present invention that it is inexpensiveand straightforward to make.

It is yet another feature of the present invention that it can be easilymodified for any type of surgical procedure.

It is a yet further feature of the present invention that it can varythe angle of the osteotomy cut.

It is an advantage of the present invention that it reduces the amountof soft tissue dissection needed to perform an osteotomy, particularlythe need for additional dissection to open the surgical area for furthercutting to correct a misalignment.

It is another advantage of the present invention that it makes osteotomyprocedures easier to perform and increases a surgeon's confidence.

These and other objects, features and advantages of the presentinvention will become apparent as the description of certainrepresentative embodiments proceeds.

SUMMARY OF THE INVENTION

The present invention provides an osteotomy guide for guiding surgicalsaw blades when making an osteotomy cut in a bone. The breakthroughdiscovery of the present invention is that an osteotomy guide, inaddition to guiding the saw blade, must also stabilize and support theblade so that the planes of opposing cuts will exactly coincide.

Accordingly, the present invention is directed to an osteotomy guide forguiding an osteotomy blade during cutting of bone, comprising a guidepin holder sized and shaped such that the guide pin holder can rotateabout a guide pin while being held at a first fixed angle relative tothe guide pin, and an osteotomy blade stabilizer connected to the guidepin holder such that the osteotomy blade stabilizer will be held at afixed angle relative to the guide pin, the osteotomy blade holder sizedand shaped such that the osteotomy blade can move translationally whilethe plane of the osteotomy blade is held at a second fixed anglerelative to the guide pin. The osteotomy guide may include having thefirst fixed angle and the second fixed angle both 180° so that the planeof the osteotomy blade is held parallel to the guide pin.

The present invention is also directed to an osteotomy guide for guidingan osteotomy blade during cutting of bone, comprising a base defining abore, the bore having a diameter such that it will rotatably hold aguide pin and having a depth such that the base will be held at a fixedangle relative to the guide pin, extending from the base, a pair ofprongs defining a slot parallel to the bore, the slot having a width anddepth such that the plane of the osteotomy blade will be held parallelto the guide pin as the osteotomy blade moves up and down through theslot, and a handle connected to the base.

The present invention is further directed to an osteotomy guide forguiding an osteotomy blade during cutting of bone, comprising a basedefining a bore, the bore having a diameter such that it will rotatablyhold a guide pin and having a depth such that the base will be held at afixed angle relative to the guide pin, extending horizontally from thebase, a pair of prongs defining a slot at a fixed angle relative to thebore, the slot having a width and depth such that the plane of theosteotomy blade will be held at a fixed angle relative to the guide pinas the osteotomy blade moves up and down through the slot, and a handleconnected to the base.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more clearly understood from a reading ofthe following detailed description in conjunction with the accompanyingdrawings wherein:

FIG. 1 is a simplified perspective view of the bones of a foot showingan exploded view of a typical bunionectomy osteotomy cut.

FIG. 2 is a perspective view of an osteotomy guide made according to theteachings of the present invention; and,

FIG. 3 is a perspective view of the osteotomy guide of FIG. 1 being usedto perform an bunionectomy on a foot, the soft tissue surrounding thebones not being shown to make the drawing easier to view.

DETAILED DESCRIPTION

Referring now to FIG. 1 of the drawings, there is shown a simplifiedperspective view of the bones of a foot 10 including an exploded view ofa typical bunionectomy osteotomy cut 12. As described in the Backgroundof the Invention, a bunion, indicated by dashed outline 14, willtypically be located at the joint 16 between the first metatarsal bone18 and the proximal phalange bone 20 of the big toe. By making cut 12 asshown and then laterally (toward the outside of foot 10) displacing themetatarsal head 22 relative to the rest of metatarsal 18, as indicatedby arrows 24, affected metatarsal phalangeal joint 16 is moved away fromwhere it will contact a patient's footware.

Osteotomy cut 12 is V-shaped so that, as described in the Background ofthe Invention, when reattached the shape of the cut will provide somestructural support. Moreover, V-shaped cut 12 must be properly alignedrelative to metatarsal head 22 or the surgery will cause furtherproblems. For example, if the apex, or axis, 26 of cut 12 is too farforward (distal) there is a risk of nonunion when the cut ends arereattached. If axis 26 of cut 12 is too far back (proximal), then ametatarsal head fracture or a vascular necrosis may result. Similarly,if axis 26 is not straight through metatarsal head 22, but is tiltedmedially or laterally (up or down) then, when reattached, metatarsalhead 22 may point in a different direction or metatarsal 18 may belonger or shorter than normal (beyond the shortening that results fromlost bone tissue from the cutting itself). An equally serious problem isthat if the planes of opposing cuts are not perfectly aligned relativeto each other, the cut ends will not align and more bone tissue will belost in correcting the misalignment.

During surgery, axis 26 is defined by a guide pin, usually a so-calledK-wire, that is drilled into metatarsal head 22. Osteotomy guides attachto the guide pin or K-wire to guide the saw blade of a hand-heldsaggital saw to make the cuts.

The problems revealed by the exemplary bunionectomy are common to allosteotomy procedures.

FIG. 2 is a perspective view of an osteotomy guide 28 made according tothe teachings of the present invention. Osteotomy guide 28 comprises ahandle 30, a base 32 and a pair of prongs 34. Base 32 has a bore 36 forpassage of a K-wire or other guide pin or axis guide. Prongs 34 define aslot 38 for passage of a surgical saw blade. Bore 36 has a diameter suchthat a guide pin will just fit inside bore 36 and a depth such thatosteotomy guide 28 will not twist or rock about the guide pin. Prongs 34are of sufficient width and separation, and slot 38 resultingly ofsufficient depth and width, so that a saw blade will be stabilized andsupported as it moves up and down through slot 38. Together, thedimensions of bore 36 and slot 38 ensure that a saw blade will be heldat a fixed angle, preferably parallel, to the guide pin.

FIG. 3 is a perspective view of osteotomy guide 28 being used to performan bunionectomy on a foot 40 (the soft tissue surrounding the bones offoot 40 are not shown to make the drawing easier to view). After aK-wire 42 is drilled into a metatarsal head 44, osteotomy guide 28 isplaced around K-wire 42 so that K-wire 42 is rotatably secured insidebore 36 and the path for each cut determined by the surgeon. The surgeonthen holds osteotomy guide 28 by handle 30, and with slot 38 securelyholding a saw blade 46 in line with K-wire 42, makes each cut. Anydeviation of saw blade 46 from the path determined by the surgeon willcreate an inaccurate and unstable osteotomy. By the use of osteotomyguide 28, the planes of each cut will intersect with K-wire 42 and theintended apex of the V-cut. This ensures a perfect "V" without the cutsconverging or diverging as they proceed laterally. All four osteotomysurfaces will then exactly coincide when the cut ends are reattached.

The angle of the "V" should be 60° for greatest stability. That is whymost prior art osteotomy guides are fixed at 60°. Some procedures,however, require a longer top (dorsal) arm osteotomy cut, such as forattachment screw placement. With osteotomy guide 28, this can beaccomplished while making certain that the saw blade remains parallelwith the K-wire for both cuts.

The preferred dimensions for an osteotomy guide sized for a conventionalbunionectomy include prong lengths of 2 cm, a guide pin bore diametersized for a 0.062 inch K-wire, and a handle 4 cm high. Persons ofordinary skill in the art will find it routine to resize the osteotomyguide for other osteotomy procedures.

The disclosed osteotomy guide successfully demonstrates the advantagesof adding a saw blade stabilizing feature to the guiding function ofprior art osteotomy guides. The disclosed guide can be used tofacilitate any surgical procedure where control of a saw blade or othercutting device and convergence of multiple cuts are required. Althoughthe disclosed guide is specialized, its teachings will find applicationin other areas where intricate procedures are performed by hand.

Those with skill in the field of the invention will readily seemodifications that can be made to the invention as described, yet stillwithin the intended scope of the claims. Therefore, all embodimentscontemplated have not been shown in complete detail. Other embodimentsmay be developed without departing from the spirit of the invention orfrom the scope of the claims.

I claim:
 1. An osteotomy guide for guiding an osteotomy blade duringcutting of bone, comprising:(a) a guide pin holder sized and shaped suchthat the guide pin holder can rotate about a guide pin while being heldat a first fixed angle relative to the guide pin; and, (b) an osteotomyblade stabilizer connected to the guide pin holder such that theosteotomy blade stabilizer will be held at a fixed angle relative to theguide pin, the osteotomy blade holder sized and shaped such that theosteotomy blade can move translationally while the plane of theosteotomy blade is held at a second fixed angle relative to the guidepin.
 2. The osteotomy guide according to claim 1, wherein the firstfixed angle and the second fixed angle are both 180° so that the planeof the osteotomy blade is held parallel to the guide pin.
 3. Anosteotomy guide for guiding an osteotomy blade during cutting of bone,comprising:(a) a base defining a bore, the bore having a diameter suchthat it will rotatably hold a guide pin and having a depth such that thebase will be held at a fixed angle relative to the guide pin; (b)extending from the base, a pair of prongs defining a slot parallel tothe bore, the slot having a width and depth such that the plane of theosteotomy blade will be held parallel to the guide pin as the osteotomyblade moves up and down through the slot; and, (c) a handle connected tothe base.
 4. An osteotomy guide for guiding an osteotomy blade duringcutting of bone, comprising:(a) a base defining a bore, the bore havinga diameter such that it will rotatably hold a guide pin and having adepth such that the base will be held at a fixed angle relative to theguide pin; (b) extending horizontally from the base, a pair of prongsdefining a slot at a fixed angle relative to the bore, the slot having awidth and depth such that the plane of the osteotomy blade will be heldat a fixed angle relative to the guide pin as the osteotomy blade movesup and down through the slot; and, (c) a handle connected to the base.